CN108008179B - Low-voltage detection circuit with built-in MCU capable of dynamically switching voltage detection points - Google Patents
Low-voltage detection circuit with built-in MCU capable of dynamically switching voltage detection points Download PDFInfo
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- CN108008179B CN108008179B CN201711233553.1A CN201711233553A CN108008179B CN 108008179 B CN108008179 B CN 108008179B CN 201711233553 A CN201711233553 A CN 201711233553A CN 108008179 B CN108008179 B CN 108008179B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16528—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values using digital techniques or performing arithmetic operations
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
- G05B19/042—Programme control other than numerical control, i.e. in sequence controllers or logic controllers using digital processors
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/20—Pc systems
- G05B2219/25—Pc structure of the system
- G05B2219/25039—Clock
Abstract
The invention discloses a low voltage detection circuit with a built-in MCU capable of dynamically switching voltage detection points, which belongs to the technical field of voltage detection, and comprises a resistor R3, wherein one end of the resistor R3 is grounded, the other end of the resistor R3 is connected with a resistor R2 and a drain electrode of an MOS transistor N1 in parallel, a source electrode of the MOS transistor N1 and the other end of the resistor R2 are connected with a resistor R1 and an inverting input end of an operational amplifier in parallel, a non-inverting input port of the operational amplifier is connected with a reference voltage Vref, a grid electrode of the MOS transistor N1 is connected with an output end of an INV1 in series, the other end of the operational amplifier is connected with a trigger T1 in series, the other end of the trigger T1 is connected with an input end of a delay unit DL1 and an input end of an INV1 in parallel through N groups of triggers D, the multiplexing of voltage detection modules is realized, one voltage detection module can realize two functions, the area of the chip is saved, and the static power consumption of the circuit is reduced.
Description
Technical Field
The invention relates to the technical field of voltage detection, in particular to a low-voltage detection circuit with a built-in MCU (microprogrammed control unit) and a dynamic switching voltage detection point.
Background
The application range of the existing MCU product is very wide, the chips can normally work when the power supply voltage is higher than a certain value, in order to ensure the stable and reliable work of the chips, more and more MCU chips are internally provided with voltage detection circuits, and when the power supply voltage is lower than a designed voltage detection point, the MCU chips generate an interrupt signal and send out a warning of low power supply voltage; if the power supply voltage continues to be reduced and is lower than the other voltage detection point, the MCU chip generates a reset signal to reset the chip, so that the abnormal working state of the chip is prevented. As shown in fig. 1, the low voltage detection circuit for implementing low voltage interrupt and low voltage reset circuit in the existing MCU circuit needs two voltage detection modules for implementing low voltage interrupt and low voltage reset functions, which results in a large chip area, increases the manufacturing cost of the chip, and also generates large power consumption. Therefore, a low voltage detection circuit with a built-in MCU capable of dynamically switching voltage detection points is provided.
Disclosure of Invention
The invention aims to provide a low-voltage detection circuit with a built-in MCU (microprogrammed control unit) capable of dynamically switching voltage detection points, so as to solve the problems that the area of a chip is larger, the manufacturing cost of the chip is increased and larger power consumption is generated in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme: a low voltage detection circuit with a built-in MCU capable of dynamically switching voltage detection points comprises a resistor R3, one end of the resistor R3 is grounded, the other end of the resistor R3 is connected with a resistor R2 and the drain of a MOS transistor N1 in parallel, the source of the MOS transistor N1 and the other end of the resistor R2 are connected with a resistor R1 and the inverting input end of an operational amplifier in parallel, the non-inverting input port of the operational amplifier is connected with a reference voltage Vref, the grid of the MOS transistor N1 is connected with the output end of an INV1 in series, the other end of the operational amplifier is connected with a trigger T1 in series, the other end of the trigger T1 is connected with the input end of a delay unit DL1 and the input end of an INV1 in parallel through an N group of triggers D, and the INV.
Preferably, the clock CLK of the flip-flop D is from the system clock of the MCU.
Preferably, the reset signals of the flip-flop T1 and the flip-flop D are from the system reset of the MCU.
Preferably, N is an integer greater than or equal to 3, and the number of N is greater than the number of clocks required to perform the interrupt.
Compared with the prior art, the invention has the beneficial effects that: according to the low-voltage detection circuit with the built-in MCU and the capability of dynamically switching the voltage detection points, the voltage detection point switching circuit is added, so that the multiplexing of the voltage detection module is realized, one voltage detection module can realize two functions of low-voltage interruption and low-voltage reset, the area of a chip is saved under the condition of ensuring the functions, and the static power consumption of the circuit is reduced.
Drawings
FIG. 1 is a low voltage detection circuit diagram for implementing a low voltage interrupt and low voltage reset circuit in a conventional MCU circuit of the present invention;
FIG. 2 is a low voltage detection circuit diagram of the present invention capable of dynamically switching voltage detection points;
FIG. 3 is a timing diagram of the delay requirement of DL1 according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 2, the present invention provides a technical solution: a low voltage detection circuit with a built-in MCU capable of dynamically switching voltage detection points comprises a resistor R3, one end of the resistor R3 is grounded, the other end of the resistor R3 is connected with a resistor R2 and the drain of a MOS transistor N1 in parallel, the source of the MOS transistor N1 and the other end of the resistor R2 are connected with a resistor R1 and the inverting input end of an operational amplifier in parallel, the non-inverting input port of the operational amplifier is connected with a reference voltage Vref, the grid of the MOS transistor N1 is connected with the output end of an INV1 in series, the other end of the operational amplifier is connected with a trigger T1 in series, the other end of the trigger T1 is connected with the input end of a delay unit DL1 and the input end of an INV1 in parallel through an N group of triggers D, and the INV.
The clock CLK of the trigger D is from the system clock of the MCU, the reset signals of the trigger T1 and the trigger D are from the system reset of the MCU, N is an integer which is greater than or equal to 3, and the number of N is greater than the number of clocks required for executing interruption.
The working principle is as follows: fig. 1 is a low voltage detection circuit for implementing a low voltage interrupt and low voltage reset circuit in an existing MCU circuit, the circuit including two voltage detection blocks, where R2/(R1+ R2) < R4/(R3+ R4), the operation of the low voltage detection circuit:
(1) when the power voltage is reduced to ensure that VDD R2/(R1+ R2) is less than Vref, the low-voltage interrupt signal is set to 1, and the MCU chip generates interrupt;
(2) the power voltage continues to decrease, and when VDD R4/(R3+ R4) is less than Vref, the low voltage reset signal is set to 1, and the MCU chip generates a reset signal.
FIG. 2 is a low voltage detection circuit capable of dynamically switching voltage detection points according to the present invention:
the circuit comprises a voltage detection module with multiple voltage detection points, a voltage point dynamic switching circuit,
wherein the content of the first and second substances,
the clock CLK of the flip-flop D1, the flip-flop D2 and the flip-flop DN in the circuit comes from the system clock of the MCU, the reset signals of the flip-flop T1, the flip-flop D1, the flip-flop D2 and the flip-flop DN in the circuit come from the system reset of the MCU, and the low level is effective.
As shown in fig. 3, when the output terminal of DN changes from 0 to 1, a certain time Trsp is required for the output terminal of the comparator to change from 1 to 0, so the delay time t1 of DL1 in the circuit must be greater than the reflection time Trsp of the comparator, otherwise the low voltage reset signal may generate glitch.
The number of the voltage detection points in the circuit is not limited to 2, and the number of the voltage detection points can be increased by increasing the number of the resistor voltage division.
The working process of the low-voltage detection circuit is as follows:
(1) in the initial state, the outputs of the T trigger T1 and the D trigger D1-DN are both 0, at the moment, the low-voltage interrupt signal is enabled, and the low-voltage reset signal is shielded; the NMOS transistor N1 is turned on.
(2) When the power supply voltage drops to such a level that VDD × R3/(R1+ R3) is less than Vref, the output of the CMP goes high, and the low interrupts signal 1.
(3) After N CLK, the output of the INV1 becomes low, the low interrupt signal is masked, the NMOS transistor N1 is turned off, the voltage detection point is switched to the detection point of the low voltage reset, and the output of the CMP becomes low.
(4) After a delay time t1 of the delay unit DL1, the output of DL1 becomes high level, and the low level reset signal is enabled.
(5) The power supply voltage continues to decrease, and when VDD × (R3+ R2)/(R1+ R2+ R3) is less than Vref, the output of the CMP goes high, the low voltage reset signal is set to 1, and the MCU chip generates the reset signal.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (4)
1. A low-voltage detection circuit with a built-in MCU capable of dynamically switching voltage detection points comprises a resistor R3 and is characterized in that: the one end ground connection of resistance R3, the other end of resistance R3 has connected in parallel resistance R2 and the drain of MOS transistor N1, the source of MOS transistor N1 and the other end of resistance R2 all have connected in parallel resistance R1 and the inverting input end of operational amplifier, the homophase input port of operational amplifier is connected with reference voltage Vref, the gate of MOS transistor N1 has connected in series the output of INV1, the other end of operational amplifier has connected in series flip-flop T1, the other end of flip-flop T1 passes through N group flip-flop D and has connected in parallel the input of delay element DL1 and the input of INV1, INV1 is the logic inverter circuit.
2. The low voltage detection circuit with built-in MCU capable of dynamically switching voltage detection point according to claim 1, characterized in that: the clock CLK of the trigger D is from the system clock of the MCU.
3. The low voltage detection circuit with built-in MCU capable of dynamically switching voltage detection point according to claim 1, characterized in that: the reset signals of the flip-flop T1 and the flip-flop D come from the system reset of the MCU.
4. The low voltage detection circuit with built-in MCU capable of dynamically switching voltage detection point according to claim 1, characterized in that: n is an integer greater than or equal to 3, and the number of N is greater than the number of clocks required for executing the interrupt.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711233553.1A CN108008179B (en) | 2017-11-30 | 2017-11-30 | Low-voltage detection circuit with built-in MCU capable of dynamically switching voltage detection points |
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| CN201711233553.1A CN108008179B (en) | 2017-11-30 | 2017-11-30 | Low-voltage detection circuit with built-in MCU capable of dynamically switching voltage detection points |
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| CN108008179A CN108008179A (en) | 2018-05-08 |
| CN108008179B true CN108008179B (en) | 2020-03-10 |
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| JP2020004119A (en) * | 2018-06-28 | 2020-01-09 | ルネサスエレクトロニクス株式会社 | Semiconductor device and control system using same |
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| JP3172095B2 (en) * | 1996-06-14 | 2001-06-04 | セイコーインスツルメンツ株式会社 | Charge / discharge control circuit and rechargeable power supply |
| CN1734269A (en) * | 2004-08-11 | 2006-02-15 | 鸿富锦精密工业（深圳）有限公司 | low-voltage detection circuit |
| CN103091526B (en) * | 2011-11-04 | 2015-02-04 | 上海华虹宏力半导体制造有限公司 | Voltage detection circuit |
| CN104467766A (en) * | 2014-12-05 | 2015-03-25 | 广州中大数码科技有限公司 | Reset circuit applied to radio frequency identification |
| CN106100621B (en) * | 2016-07-22 | 2018-10-30 | 天津大学 | A kind of automatic reset structure for clock handoff procedure |
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